REVIEWS. 
71 
fauna, which often are nothing more than generic, and sometimes sink 
into mere specific differences. From this has arisen a glaring and dis¬ 
agreeable want of uniformity, which might easily have been avoided, and 
therefore ought to have been so. In the construction of the family 
characters, the veining of the wings has not everywhere obtained the 
attention it deserves, as an easily observable and in general very sure 
guide. This defect is partially supplied by the good figures, from the 
hand of Mr. Westwood, which accompany the work : where this illustration 
is wanting, the omission is felt all the more sensibly. 
Proceeding now to take up, one by one, the families of the Brcichycera 
admitted by Mr. Walker, we shall briefly give the most material remarks 
that suggest themselves, touching, their definition or limits. 
1. StratiomydcE. —Contrary to general usage, the author has united 
with this family the genera Beris and Actina ; an extension of it in 
which we concur, since these genera undoubtedly approach much closer to 
the rest of the Stratiomydce than to the Xylophagidce , with which they 
are generally associated by the authors who do not admit the Beridce as 
a family by itself. It were to be desired that Mr. Walker had given 
greater prominence to the sub-divisions of this as well as other extensive 
families. This would have afforded a link of connection with other 
modern arrangements of the order, more interesting and more practical 
than the unnecessarily diffuse and quite useless repetition of obsolete 
family names among the synonyms. In the general character, the phrase 
11 palpi most often clavate” is unsatisfactory; these organs might have 
been more correctly characterised as obsolete in some genera, three-jointed 
in the rest. The antennae are described as five to ten-jointed ; this is 
wrong, not one of the genera given by Mr. Walker having less than eight 
joints; and the expression, “articuli tertius et sequentes subsequales,” is 
far from exact. The number of segments ascribed to the abdomen (five) 
is incorrect: in the genera Beris and Actina seven are visible; in the 
rest the actual number is the same, but the sixth and seventh segments 
are retracted under the fifth; in Sargus and Chrysomyia the seventh is 
at its minimum of development. To prevent misapprehension, it should 
have been stated that the anterior branch of the cubital vein is regularly 
wanting in some species ; for instance, Nemotelus nigrinus 1 Stratiomys 
microleon , S. argentata , etc., and disappears occasionally in individual 
specimens, of the genus Beris for example. 
2. Xylophagidce. —The terminal segments of the abdomen are described 
as tubular in the female ; this is true of the genus Xylophagus , but not of 
